“There was a period of great love between them,” says Ingrid Seward

Janine Henni is a Royals Staff Writer for PEOPLE Digital, covering modern monarchies and the world’s most famous families. Like Queen Elizabeth, she loves horses and a great tiara moment.

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Then-Prince Charles and Princess Diana on their honeymoon at Balmoral Castle in Scotland in August 1981. Photo: Kent Gavin /Mirrorpix/Getty

Princess Diana hoped the world would know about the love that the future King Charles sent her through letters, a royal biographer claims.

Though Diana and Charles’ relationship ended in divorce in 1996, the late Princess of Wales wanted the public to see the love letters that the future monarch sent early in their romance so people would know that their affection had been genuine, The Times reported on July 23.

“Diana told me very shortly before she died that she wished people could see the love letters that she had from Charles,” royal biographer Ingrid Seward said at an Oldie magazine lunch, according to the outlet.

“She really wanted people to know that she loved Charles and he loved her. And I always remembered that. And she wanted the boys [Prince William and Prince Harry] to know that,” she continued. “There was a period of great love between them.”

Princess Diana and Prince Charles on their July 29, 1981 wedding day.Terry Fincher/Princess Diana Archive/Getty

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Seward said that Princess Diana expressed the sentiment about the correspondence from the then-Prince Charles just a few weeks before she died following a car accident in Paris in 1997. Though Diana was then dating Dodi Fayed, who also died in the accident, the royal commentator claimed that she wanted “the early days of her romance with the heir to the throne to be properly reflected,” The Times reported.

It remains unclear which years the late Princess of Wales received the love letters that she was referencing. Diana and Charles married in 1981 following a short courtship (she said they only met 13 times before he proposed) and went on to welcome Prince William in 1982 and Prince Harry in 1984.

Princess Diana reportedly told Andrew Morton, journalist and author of Diana: Her True Story, that she and the future King Charles “were very, very close to each other the six weeks before Harry was born, the closest we’ve ever, ever been and ever will be,” referring to the late summer of 1984.

Princess Diana, Prince William and Prince Charles in the gardens of their home at Kensington Palace in London on June 12, 1984.Keystone/Hulton Archive/Getty

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Retired British Army captain James Hewitt also claimed to have begun an affair with Diana around 1986, which he said lasted for the next five years. In a 1994 ITV interview with biographer Jonathan Dimbleby, the future King Charles said that he was faithful to his wife, “Until it became irretrievably broken down, us both having tried,” The New York Times reported.

By the time she sat for an interview with the BBC’s Panorama in 1995, however, Diana shared a harsher side of the story. A breakout revelation was her comment on the disintegration of her marriage to Prince Charles when she famously said, “There were three of us in this marriage, so it was a bit crowded,” referring to his extramarital affair with the future Queen Camilla.

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Prince Charles and Princess Diana at a Presidential banquet at the Blue House in Seoul during their last official trip together in the Republic of Korea.Tim Graham Photo Library/Getty

Today, the whereabouts of the alleged love letters are unclear. Interest in the “People’s Princess,” as then-Prime Minister Tony Blair famously memorialized Diana following her untimely death at age 36, remains sky-high.

Some of her intimate letters to friends during her divorce from then-Prince Charles sold at auction last year for just under $170,000.